The invention generally relates to medical devices for retrieving material from within a body. More particularly, the invention relates to medical retrieval baskets that have a projection proximally extending from a distal tip of the basket to enhance the basket""s ability to secure or fragment material (e.g., stones) captured from a body lumen.
Medical baskets are used to retrieve biological material from a body. For example, medical baskets are commonly used to retrieve stones from a patient""s urinary tract or biliary tree. Medical baskets may or may not be used through a catheter, an endoscope, or a laparoscope.
Existing medical baskets generally have two or more legs, which are joined together to form the basket. The number, flexibility, shape, and length of the legs defines an overall shape of a particular medical basket. At a proximal base of the basket, the joined legs typically are attached to an elongated member, such as, for example, a shaft, wire, or coil. The elongated member can be moved back and forth within a sheath or catheter by an actuation device, such as, for example, a back-and-forth hand-activated slider located on the proximal end of the sheath. Alternatively, the sheath can move back and forth to expose and cover the basket. In any case, the basket is fully expanded when exposed, fully collapsed when covered by the sheath, or somewhere in between these two extremes.
To retrieve a stone or other biological material from the patient""s body, a medical professional, such as a physician, inserts a device including the medical basket into the patient""s body, locates the stone, captures the stone within the basket by first expanding the basket and then collapsing the basket around the stone. Finally the medical professional removes the device with captured stone from the patient""s body. In some cases, the medical professional may desire to crush or break the stone into smaller pieces in situ prior to removal to facilitate natural passage of the stone or to facilitate removal of the stone within the basket. In these cases, a procedure known as lithotripsy can be performed through a catheter device attached to the basket.
It is an object of the invention to provide a medical instrument for treating material in a patient""s body. The medical instrument includes a basket having a plurality of basket legs and a projection extending from the distal end of the basket proximally into a basket lumen. The plurality of basket legs and the projection secures material captured within the basket lumen and inhibits material from escaping from the medical instrument. The projection may also assist in breaking apart material captured within the basket lumen.
It is another object of the invention to provide a medical instrument that allows material to be captured, fragmented, and retrieved from a patient""s body. The medical instrument further includes a lithotriptor that can access material captured within the basket.
It is yet another objection of the invention to provide a method of using such baskets to retrieve material from within a body. The material can be, for example, urological stones or any variety of other types of material found in the body.
A device for treating material in a body according to one aspect of the invention includes a sheath and an expandable basket. The sheath includes a sheath wall, a distal end, a proximal end, and a lumen extending within the sheath. The expandable basket is slidably receivable by the lumen of the sheath and has a collapsed position where the basket is enclosed within the sheath and an expanded position where the basket extends from the distal end of the sheath. The basket includes a distal tip, a proximal end, a lumen, and a projection. The projection has a distal end joined to the distal tip of the basket and a proximal end that is free within the lumen of the basket.
In accordance with one aspect of the invention, the device may include a projection having at least one tip. The tip may be sharp to facilitate breakage of the material captured within the basket. The device may further include the following features. The device may have an elongated member axially positioned within the lumen of the sheath and operatively joined to the proximal end of the basket. The elongated member may include a lumen extending therethrough and in fluid communication with the basket lumen to allow the passage of a lithotriptor or liquids to pass through the elongated member to the basket lumen. In one embodiment, a basket handle for controlling the position of the basket may be positioned at the proximal end of the sheath. The handle may include a spring operatively joined to the elongated member. The spring provides a predetermined force on the basket to withdraw the basket legs into the sheath upon the handle""s release. In an alternative embodiment, the handle may include a slider to move the sheath axially from a first position to a second position to expose and cover the basket. The device may further include a reinforced distal end to prevent damage to the sheath during movement of the sheath from the first position to the second position.
The device may also include a lithotriptor for fragmenting material captured within the basket. In one embodiment the lithotriptor includes an energy source, an actuator, and a return spring. In an alternative embodiment, the lithotriptor includes an optical cable and a laser. In another embodiment, the device may include a wire for deflecting the sheath. The wire includes a distal portion, an intermediate portion, and a proximal portion. The distal portion of the wire is attached to the distal end of the sheath. In some embodiments, the wire extends along an external surface of the sheath, the intermediate portion of the wire penetrates the sheath wall, and the proximal portion extends proximally within the lumen of the sheath. In an embodiment of the device including the wire for deflection of the sheath, the device may include an elongated member including a distal portion and a proximal portion. The distal portion of the elongated member includes an elastic material, such as, a shape memory alloy or a spring that can be deflected with the sheath and then return to its original shape.
Another aspect of the invention relates to a method for retrieving material from a body including the steps of inserting a device including a basket with a projection, such as the baskets described above into a patient""s body, placing the basket in an expanded position, maneuvering the basket to grasp the material, collapsing the basket around the material, and withdrawing the device from the body to remove the grasped material from the body.
The foregoing and other objects, aspects, features, and advantages of the invention will become more apparent from the following description and from the claims.